Question: What effects does arsenic have at the minimal lethal dose of 300?
Paraphrase: Arsenic has a minimal lethal dose of 300; what effects does it have at that level?
SPARQL (Wikidata): SELECT ?value WHERE { wd:Q871 p:P2300 ?s . ?s ps:P2300 ?x filter(contains(?x , '300.0')) . ?s pq:P689 ?value}